When you are using a TabletPC with a digitizer having a backup pen is always a good idea. But a replacement pen from Microsoft will cost you $49.99. But what about if I tell you that you can buy a backup pen for as low as $9.25 (affiliated link).
The HTC Scribe is a pen sold under the HTC brand but the technology behind is from N-Trig, the same company that made the Pen sold with the Surface PRO 3. Now, do not let the fact that the above link is marked as an affiliated link fool you, this article was written using this Pen is my Surface PRO 3.
The technical characteristics of this Pen are the same as in the Surface PRO 3 so the experience while using it is about the same. There are two major differences between both pens, one of them is the tip.
The one on the left in the above picture is the one used in the Surface PRO 3. Comparing both it seems better built the one from the HTC Scribe.
The HTC Scribe pen is harder and you feel the difference when you are writing. The pen in the Surface PRO 3 is a lot softer and that makes the writing experience more natural but you will need to change the tip more often.
The second difference between the two pen is that the HTC Scribe does not have a top button capable of interacting with OneNote. This means that the HTC Scribe uses only one AAAA battery and does not have a BT transmitter. Unfortunately, both top caps were built using different threads as you can see in the below picture and that means that you can't use the BT cap from the PRO in the HTC Scribe.
The HTC Scribe is a wonderful spare pen for the Surface PRO 3 if you don't mind losing the features associated with OneNote. Overall, the Pen works very well, I would say that probably better than the one included in the Surface PRO 3. In my opinion the tip on this one is able to transmit better the differences grades of pressures that you are putting in the Tip. But that's just my opinion.